In a sole-support plate of this type, which is known for example from Swiss Pat. No. 47 78 90, the pivot bearing is formed by a screw which secures the sole plate on the upper side of the ski. The sole-support plate can be pivoted a limited amount to both sides of the ski about this pivot bearing from a base or original position in which it is parallel to the longitudinal axis of the ski. The end of the sole-support plate remote from the pivot bearing is constructed as a spring cage in which, between the upper side of the ski and the bottom of the sole-support plate, two arcuate springs are provided which are supported on a ski-fixed stop. These springs press with an initial tension against lateral stops provided on the sole-support plate. During lateral swinging of the sole-support plate from its base position, at least one of the springs will be elastically deformed and, after the release of the ski shoe, will urge the sole-support plate back to its base position. The structure here is relatively complex, as many individual parts are needed which are difficult to mount and are exposed to a heavy wear. This zero adjuster therefore cannot assure a constant swing-out resistance for the sole-support plate, which is important for maintaining constant friction conditions during the release of the ski binding. Furthermore, in order to protectively encase the zero adjuster, a considerable height is needed for the release plate.
Austrian Pat. No. 3l0 626 discloses a sole-support device for a release ski binding which includes a U-shaped wire bar, the leg ends of which are anchored in a base plate which is secured on the ski. The legs, which in the original or base position extend approximately parallel with respect to the longitudinal direction of the ski, carry cylindrical rollers which rest on the underside of the ski shoe sole. During a swinging out of the ski shoe, the ski shoe bends, by means of the rollers, the legs of the bar parallel to the upper side of the ski so that the bearing areas of the ski shoe sole move in the swing-out direction. As soon as the ski shoe comes free from a binding part which is adjacent to the sole-support device, the pressure exerted by the ski shoe sole on the rollers is eliminated and the legs of the bar spring back again. Since the anchoring of the bar and the swivel axis of the ski shoe lie opposite during swinging out, a relative and opposite movement takes place between the underside of the ski shoe sole and the rollers or the legs of the bar, during which movement no clear friction relationship exists between the ski shoe sole and the rollers, which is a disadvantage, and more so because the contact areas between the ski shoe sole and the rollers are extraordinarily small. Also, one must fear that snow present in the bearing areas can reduce the friction between the ski shoe sole and the rollers sufficiently so that the bar is not deformed at all during a swinging out of the ski shoe. Thus, it cannot be assured that, during all release operations, friction conditions exist which are consistent and predictable and can be considered in relationship to the release behavior of the ski binding right from the start, particularly since snow and dirt can penetrate substantially unhindered into the inside of the support device between the ski upper side and the underside of the ski shoe.
One purpose of the invention is thus to provide a sole-support plate of the above-mentioned type which includes as few individual parts as possible and assures a constant swing-out resistance and thus constant friction conditions in the safety ski binding.